Rheumatoid arthritis is an autoimmune disease triggered by Proteus urinary tract infection

Patient-Derived Microphysiological Systems for Precision Medicine

Patient-derived microphysiological systems (P-MPS) have emerged as powerful tools in precision medicine that provide valuable insight into individual patient characteristics. This review discusses the development of P-MPS as an integration of patient-derived samples, including patient-derived cells, organoids, and induced pluripotent stem cells, into well-defined MPSs. Emphasizing the necessity of P-MPS development, its significance as a nonclinical assessment approach that bridges the gap between traditional in vitro models and clinical outcomes is highlighted. Additionally, guidance is provided for engineering approaches to develop microfluidic devices and high-content analysis for P-MPSs, enabling high biological relevance and high-throughput experimentation. The practical implications of the P-MPS are further examined by exploring the clinically relevant outcomes obtained from various types of patient-derived samples. The construction and analysis of these diverse samples within the P-MPS have resulted in physiologically relevant data, paving the way for the development of personalized treatment strategies. This study describes the significance of the P-MPS in precision medicine, as well as its unique capacity to offer valuable insights into individual patient characteristics.

Urine microbiome in individuals with an impaired immune system

With the advent of next generation sequencing, it is now appreciated that human urine is not sterile. Recent investigations of the urinary microbiome (urobiome) have provided insights into several urological diseases. Urobiome dysbiosis, defined as non-optimal urine microbiome composition, has been observed in many disorders; however, it is not clear whether this dysbiosis is the cause of urinary tract disorders or a consequence. In addition, immunologically altered disorders are associated with higher rates of urinary tract infections. These disorders include immunoproliferative and immunodeficiency diseases, cancer, and immunosuppressant therapy in transplant recipients. In this review, we examine the current state of knowledge of the urobiome in immunologically altered diseases, its composition and metabolomic consequences. We conclude that more data are required to describe the urobiome in immune altered states, knowledge that could facilitate understanding the role of the urobiome and its pathophysiological effects on urinary tract infections and other disorders of the urinary tract.

Antibody Cross-Reactivity in Auto-Immune Diseases

Autoimmunity is defined by the presence of antibodies and/or T cells directed against self-components. Although of unknown etiology, autoimmunity commonly is associated with environmental factors such as infections, which have been reported to increase the risk of developing autoimmune diseases. Occasionally, similarities between infectious non-self and self-tissue antigens may contribute to immunological cross-reactivity in autoimmune diseases. These reactions may be interpreted as molecular mimicry, which describes cross-reactivity between foreign pathogens and self-antigens that have been reported to cause tissue damage and to contribute to the development of autoimmunity. By focusing on the nature of antibodies, cross-reactivity in general, and antibody-antigen interactions, this review aims to characterize the nature of potential cross-reactive immune reactions between infectious non-self and self-tissue antigens which may be associated with autoimmunity but may not actually be the cause of disease onset.

A Shifted Urinary Microbiota Associated with Disease Activity and Immune Responses in Rheumatoid Arthritis

Recent evidence emphasized the role of the microbiota in the etiopathogenesis of rheumatoid arthritis (RA). Indeed, it has been demonstrated that urinary tract infections are implicated in RA pathogenesis. However, a definitive association between the urinary tract microbiota and RA remains to be investigated. Urine samples from 39 patients affected by RA, including treatment-naive patients, and 37 age- and sex-matched healthy individuals were collected. In RA patients, the urinary microbiota showed an increase in microbial richness and a decrease in microbial dissimilarity, especially in treatment-naive patients. A total of 48 altered genera with different absolute quantities were detected in patients with RA. The 37 enriched genera included Proteus, Faecalibacterium, and Bacteroides, while the 11 deficient genera included Gardnerella, Ruminococcus, Megasphaera, and Ureaplasma. Notably, the more abundant genera in RA patients were correlated with the disease activity score of 28 joints-erythrocyte sedimentation rates (DAS28-ESR) and an increase in plasma B cells. Furthermore, the altered urinary metabolites, such as proline, citric acid, and oxalic acid, were positively associated with RA patients, and they were closely correlated with urinary microbiota. These findings suggested a strong association between the altered urinary microbiota and metabolites with disease severity and dysregulated immune responses in RA patients. IMPORTANCE We revealed that the profile of the urinary tract microbiota in RA featured with increased microbial richness and shifted taxa, associated with immunological and metabolic changes of the disease, underlining the interplay between urinary microbiota and host autoimmunity.

Immune dysregulation and pathogenic pathways mediated by common infections in rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the world's most prevalent inflammatory autoimmune diseases, affecting between 0.4 and 1.3% of the population. The susceptibility to RA appears to be influenced by a complex interaction between a favorable genetic background and the existence of a specific immune reaction against a wide range of environmental variables. Among the known environmental variables, infections are believed to have a significant role in promoting the formation of autoimmune disorders, which are frequently caused by specific microorganisms. Infections have been linked to RA in recent medical studies. In this study, we selected the most prevalent infections associated with RA from the literature and described the data confirming their pathogenic role in RA. Our investigation included Mycobacterium, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Proteus mirabilis, Epstein-Barr virus, parvovirus, and Prevotella copri.

Antibodies Isolated from Rheumatoid Arthritis Patients against Lysine-Containing Proteus mirabilis O3 (S1959) Lipopolysaccharide May React with Collagen Type I

Most rheumatic diseases, including rheumatoid arthritis (RA), are characterized by immune disorders that affect antibody activity. In the present study, using Dot blot and ELISA assay, we showed that patients with rheumatic disease produced significantly more antibodies against lipopolysaccharide (LPS) P. mirabilis O3 compared to healthy donors (p < 0.05), and affinity purified antibodies against LPS O3 may cross-react with collagen type I. It was demonstrated that purified of antibodies isolated from RA patients sera, reacted stronger with the collagen than healthy donors (p = 0.015), and cross-reaction was correlated with level of anti-citrullinated peptide antibodies (r = 0.7, p = 0.003). Moreover, using six different lipopolysaccharides were demonstrated the significant correlations in sera reactivity among lysine-containing lipopolysaccharides observed in patients’ sera (p < 0.05). Using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) it was shown that unique wavenumbers of sera spectra correlate with reactivity with lipopolysaccharides allowing distinguish patients from healthy blood donors. Antibodies adsorption by synthetic antigens shows that in patients’ group anti-LPS O3 antibodies can be adsorbed by both amides of galacturonic acid and lysine or threonine, which suggests less specificity of antibodies binding with non-carbohydrate LPS component. The observed correlations suggest that non-carbohydrate components of LPS may be an important epitope for less specific anti-LPS antibodies, which might lead to cross-reactions and affect disease development.

Role of Infections in the Pathogenesis of Rheumatoid Arthritis: Focus on Mycobacteria

Rheumatoid arthritis (RA) is a systemic inflammatory autoimmune disease characterized by chronic erosive polyarthritis. A complex interaction between a favorable genetic background, and the presence of a specific immune response against a broad-spectrum of environmental factors seems to play a role in determining susceptibility to RA. Among different pathogens, mycobacteria (including Mycobacterium avium subspecies paratuberculosis, MAP), and Epstein–Barr virus (EBV), have extensively been proposed to promote specific cellular and humoral response in susceptible individuals, by activating pathways linked to RA development. In this review, we discuss the available experimental and clinical evidence on the interplay between mycobacterial and EBV infections, and the development of the immune dysregulation in RA.

Molecular characterisation of the synovial fluid microbiome in rheumatoid arthritis patients and healthy control subjects

METHODS

The presence and identity of bacterial and fungal DNA in the synovial fluid of rheumatoid arthritis (RA) patients and healthy control subjects was investigated through amplification and sequencing of the bacterial 16S rRNA gene and fungal internal transcribed spacer region 2 respectively. Synovial fluid concentrations of the cytokines IL-6, IL-17A, IL22 and IL-23 were determined by ELISA.

RESULTS

Bacterial 16S rRNA genes were detected in 87.5% RA patients, and all healthy control subjects. At the phylum level, the microbiome was predominated by Proteobacteria (Control = 83.5%, RA = 79.3%) and Firmicutes (Control = 16.1%, RA = 20.3%), and to a much lesser extent, Actinobacteria (Control = 0.2%, RA = 0.3%) and Bacteroidetes (Control = 0.1%, RA = 0.1%). Fungal DNA was identified in 75% RA samples, and 88.8% healthy controls. At the phylum level, synovial fluid was predominated by members of the Basidiomycota (Control = 53.9%, RA = 46.9%) and Ascomycota (Control = 35.1%, RA = 50.8%) phyla. Statistical analysis revealed key taxa that were differentially present or abundant dependent on disease status.

CONCLUSIONS

This study reports the presence of a synovial fluid microbiome, and determines that this is modulated by disease status (RA) as are other classical microbiome niches.

The genetic pathogenesis, diagnosis and therapeutic insight of rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease that causes chronic inflammation of the joints. RA is a heterogeneous disorder caused by an abnormal autoimmune response triggered by the complex interactions of genetic and environmental factors that contribute to RA etiology. However, its underlying pathogenic mechanisms are yet to be fully understood. In this review, I provide an overview of the pathogenesis, diagnosis and therapeutic insight in the clinical management of RA in light of the recent updates to classification criteria and recent discoveries of genetic loci associated with susceptibility for RA.

Plantago squarrosa Murray extracts inhibit the growth of some bacterial triggers of autoimmune diseases: GC-MS analysis of an inhibitory extract

Ankylosing spondylitis, multiple sclerosis, rheumatoid arthritis and rheumatic fever are autoimmune inflammatory diseases that may be triggered in genetically susceptible individuals by specific bacterial pathogens. Inhibiting the growth of these bacteria with high antioxidant plant extracts may inhibit the aetiology of these diseases, as well as inhibiting the later phase symptoms. P. squarrosa extracts were analysed for antioxidant activity using a DPPH free radical scavenging assay. Bacterial growth inhibitory activity was evaluated using disc diffusion assays and the activity was quantified by MIC determination. The extracts were screened for toxicity by A. franciscana nauplii assays. The most potent antibacterial extract (ethyl acetate) was analysed by GC-MS headspace profile analysis and compounds were identified with reference to a phytochemical database. All extracts displayed strong DPPH radical scavenging activity. The ethyl acetate extract was particularly potent (IC₅₀ 1.4 µg/mL), whilst the other extracts also had significant radical scavenging activity (IC₅₀ values between 11 and 22 µg/mL). Notably, the bacterial growth inhibitory activity of the extracts correlated with their DPPH radical scavenging activity. The ethyl acetate extract, which had the greatest DPPH scavenging activity, generally displayed the most potent bacterial growth inhibitory activity. This extract was particularly potent against P. mirabilis, P. vulgaris and A. baylyi (MIC values of 484, 575 and 880 µg/mL, respectively). It also inhibited P. aeruginosa and S. pyogenes growth, albeit with higher MICs (1600-3700 µg/mL). All other extract-bacteria combinations were either inactive or resulted in mid-low potency inhibition. All extracts were non-toxic in the A. franciscana bioassay (LC₅₀ substantially > 1000 µg/mL). In total, 89 unique mass signals were identified in the P. squarrosa ethyl acetate extract by non-biased GC-MS headspace analysis. A number of compounds which may contribute to the antibacterial activity of this extract have been highlighted.

Novel tool in rheumatoid arthritis diagnosis-The usage of urease flap region peptidomimetics

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease. Early diagnosis can prevent joint erosion. However, available biomarkers do not always allow for clear distinction between RA and non-RA individuals. It has become known that bacteria/viruses are among the environmental triggers that initiate RA via multiple molecular mechanisms. Thus, to better understand the role of bacteria in RA, we synthetized 6 peptidomimetics of bacterial ureases' flap region. These peptides were then used to distinguish RA patients from healthy people sera by immunoblotting. Most patients' sera were bound to peptidomimetic characteristic for Enterobacter sp. and Klebsiella sp. flap urease. We also found similarities between peptidomimetic sequence and human proteins connected with RA. This pilot study suggests that bacteria may trigger RA via mechanism of molecular mimicry of urease to host proteins and ureases flap peptidomimetics may be potential candidate as a new additional diagnostic test.

Phytochemistry and Pharmacology of Phyllanthus niruri L.: A Review

Phyllanthus niruri, a typical member of family Euphorbiaceae, is a small annual herb found throughout the tropical and subtropical regions of both hemispheres. The genus Phyllanthus has been used in traditional medicine for its wide range of pharmacological activities like antimicrobial, antioxidant, anticancer, antiinflammatory, antiplasmodial, antiviral, diuretic and hepatoprotective. This review summarizes the information about morphological, biochemical, ethanobotanical, pharmacological, biological and toxicological activities with special emphasis on mechanism of anticancer activity of P. niruri. Gaps in previous studies such as taxonomic inconsistency of P. niruri, novel phytochemicals and their therapeutic properties, especially mechanisms of anticancerous activity and market products available, have been looked into and addressed. Scientific information related to 83 phytochemicals (including many novel compounds detected recently by the authors) has been provided in a very comprehensive manner. Copyright © 2017 John Wiley & Sons, Ltd.

Environmental Basis of Autoimmunity

The three common themes that underlie the induction and perpetuation of autoimmunity are genetic predisposition, environmental factors, and immune regulation. Environmental factors have gained much attention for their role in triggering autoimmunity, with increasing evidence of their influence as demonstrated by epidemiological studies, laboratory research, and animal studies. Environmental factors known to trigger and perpetuate autoimmunity include infections, gut microbiota, as well as physical and environmental agents. To address these issues, we will review major potential mechanisms that underlie autoimmunity including molecular mimicry, epitope spreading, bystander activation, polyclonal activation of B and T cells, infections, and autoinflammatory activation of innate immunity. The association of the gut microbiota on autoimmunity will be particularly highlighted by their interaction with pharmaceutical agents that may lead to organ-specific autoimmunity. Nonetheless, and we will emphasize this point, the precise mechanism of environmental influence on disease pathogenesis remains elusive.

Beyond Urinary Tract Infections (UTIs) and Delirium: A Systematic Review of UTIs and Neuropsychiatric Disorders

Urinary tract infections (UTIs) are among the most common bacterial infections. Although comorbid UTI in geriatric patients with delirium or dementia is well known, the prevalence and scope of the association with other neuropsychiatric disorders is unclear. We performed a systematic review of the association between UTIs and delirium, dementia, psychotic disorders, and mood disorders in hospitalized patients. We identified studies by searching PubMed, PsycInfo, and Web of Knowledge, and the reference lists of identified studies and review papers. Seventeen publications met the inclusion criteria. The primary findings were: (1) 88% of publications reported a positive association between UTIs and neuropsychiatric disorders; (2) 47% reported that the clinical course of a neuropsychiatric disorder may be precipitated or exacerbated by a UTI; (3) the mean weighted prevalence of UTIs in subjects was 19.4% for delirium, 11.2% for dementia, 21.7% for nonaffective psychotic disorders, and 17.8% for mood disorders. Our findings, which must be interpreted carefully given the heterogeneity among the studies, suggest that UTIs are highly comorbid in hospitalized patients and may precipitate or exacerbate some neuropsychiatric disorders. The association extends beyond geriatric patients with delirium, affects males and females, and includes adults with psychotic and mood disorders. These findings underscore the important interface between physical and mental health. Potential underlying mechanisms are also reviewed, including complex interactions between the immune system and the brain.

The potential of selected Australian medicinal plants with anti-Proteus activity for the treatment and prevention of rheumatoid arthritis

Background:

A wide variety of herbal medicines are used in indigenous Australian traditional medicinal systems to treat rheumatoid arthritis (RA) and inflammation. The current study was undertaken to test the ability of a panel of Australian plants with a history of the ethnobotanical usage in the treatment of inflammation for the ability to block the microbial trigger of RA.

Materials and Methods:

One hundred and six extracts from 40 plant species were investigated for the ability to inhibit the growth of the bacterial trigger of RA (Proteusmirabilis). The extracts were tested for toxicity in the Artemia nauplii bioassay. The most potent inhibitor of P.mirabilis growth was further analyzed by reversed-phase high performance liquid chromatography (RP-HPLC) coupled to high accuracy time-of-flight (TOF) mass spectroscopy.

Results:

Sixty-five of the 106 extracts tested (61.3%) inhibited the growth of P. The Aleurites moluccanus, Datura leichardtii, Eucalyptus major, Leptospermum bracteata, L. juniperium, Macadamia integriflora nut, Melaleuca alternifolia, Melaleuca quinquenervia, Petalostigma pubescens, P. triloculorae, P. augustifolium, Scaevola spinescens, Syzygiumaustrale, and Tasmannia lanceolata extracts were determined to be the most effective inhibitors of P. mirabilis growth, with minimum inhibitory concentration (MIC) values generally significantly below 1000 μg/ml. T. lanceolata fruit extracts were the most effective P. mirabilis growth inhibitors, with a MIC values of 11 and 126 μg/ml for the methanolic and aqueous extracts, respectively. Subsequent analysis of the T. lanceolata fruit extracts by RP-HPLC coupled to high-resolution TOF mass spectroscopy failed to detect resveratrol in either T. lanceolata fruit extract. However, the resveratrol glycoside piceid and 2 combretastatin stilbenes (A-1 and A-4) were detected in both T. lanceolata fruit extracts. With the exception of the Eucalyptus and Syzygium extracts, all extracts exhibiting Proteus inhibitory activity were also shown to be nontoxic, or of low toxicity in the Artemia nauplii bioassay.

Conclusions:

The low toxicity of these extracts and their inhibitory bioactivity against Proteus spp. indicate their potential in blocking the onset of rheumatoid arthritis.

A Potential Link between Environmental Triggers and Autoimmunity

Autoimmune diseases have registered an alarming rise worldwide in recent years. Accumulated evidence indicates that the immune system's ability to distinguish self from nonself is negatively impacted by genetic factors and environmental triggers. Genetics is certainly a factor, but since it normally takes a very long time for the human genetic pattern to change enough to register on a worldwide scale, increasingly the attention of studies has been focused on the environmental factors of a rapidly changing and evolving civilization. New technology, new industries, new inventions, new chemicals and drugs, and new foods and diets are constantly and rapidly being introduced in this fast-paced ever-changing world. Toxicants, infections, epitope spreading, dysfunctions of immune homeostasis, and dietary components can all have an impact on the body's delicate immune recognition system. Although the precise etiology and pathogenesis of many autoimmune diseases are still unknown, it would appear from the collated studies that there are common mechanisms in the immunopathogenesis of multiple autoimmune reactivities. Of particular interest is the citrullination of host proteins and their conversion to autoantigens by the aforementioned environmental triggers. The identification of these specific triggers of autoimmune reactivity is essential then for the development of new therapies for autoimmune diseases.

A review of serological tests to assist diagnosis of reactive arthritis: critical appraisal on methodologies

On a population-based level, the incidence of reactive arthritis (ReA) is 0.6–27/100,000. The definition of ReA varies and its pathogenesis is not yet clear. Attempts in basic immunology to suggest hypotheses for proliferation of forbidden B cell clones, molecular mimicry, and involvement of cross-reactive antibodies are helpful but not sufficient. Importantly, for the clinical diagnosis of the preceding infection, serology is widely used. Unfortunately, the accuracy of associations between serologic findings and clinical conclusions is plagued by poor standardization of methods. So far, few attempts have been done to examine the pitfalls of different approaches. Here, we review several serologic techniques, their performance and limitations. We will focus on serology for Yersinia, Campylobacter, Salmonella, Shigella, and Chlamydia trachomatis because these bacteria have a longer history of being associated with ReA. We also address controversies regarding the role of serology for some other bacteria linked to autoimmune disorders.

Anti-Proteus activity of some South African medicinal plants: their potential for the prevention of rheumatoid arthritis

A wide variety of herbal remedies are used in traditional African medicine to treat rheumatoid arthritis (RA) and inflammation. Thirty-four extracts from 13 South African plant species with a history of ethnobotanical usage in the treatment of inflammation were investigated for their ability to control two microbial triggers for RA (Proteus mirabilis and Proteus vulgaris). Twenty-nine of the extracts (85.3 %) inhibited the growth of P. mirabilis and 23 of them tested (67.7 %) inhibited the growth of P. vulgaris. Methanol and water extracts of Carpobrotus edulis, Lippia javanica, Pelargonium viridflorum, Ptaeroxylon obliquum, Syzygium cordatum leaf and bark, Terminalia pruinoides, Terminalia sericea, Warburgia salutaris bark and an aqueous extract of W. salutaris leaf were effective Proteus inhibitors, with MIC values <2,000 μg/ml. The most potent extracts were examined by Reverse phase high performance liquid chromatography and UV-Vis spectroscopy for the presence of resveratrol. Only extracts from T. pruinoides and T. sericea contained resveratrol, indicating that it was not responsible for the anti-Proteus properties reported here. All extracts with Proteus inhibitory activity were also either non-toxic, or of low toxicity in the Artemia nauplii bioassay. The low toxicity of these extracts and their inhibitory bioactivity against Proteus spp. indicate their potential for blocking the onset of rheumatoid arthritis.

Each type of cause that initiates rheumatoid arthritis or RA flares differentially affects the response to therapy

The autoimmune disease rheumatoid arthritis (RA) presents difficulty in diagnosis, commonly observed flare ups, polycyclical nature of RA progression, and variable response to therapies. Congruent with multiple causes, literature has documented various infectious agents, environmental factors, physical trauma, silica and food sensitivities as potential causes of RA or RA flares in different populations. We propose that these>36 events can initiate RA or RA flares which complicates treatment decisions. Each pharmaceutical medicine benefits 15-82% of RA patients. Predictive factors are needed. Because the initiating cause of RA or RA flare affects the type of joint damage, initial inflammatory response, adaptive immune response, and potential molecular mimicry, we propose the "RA cause affects response to therapy" (RACART) theory. The potential cause combined with confounding factors such as genetic risk factors, nutritional status, epigenetic status, inflammatory levels, and detoxification ability may help predict responses to various therapies.

The human Ku autoantigen shares amino acid sequence homology with fungal, but not bacterial and viral, proteins

CONTEXT

Molecular mimicry between autoantigens and microbial antigens is a possible triggering mechanism of autoimmunity. Human Ku is a DNA-associated autoantigen targeted by autoantibodies in patients with systemic lupus erythematosus and related disorders; available data are consistent with a role of molecular mimicry in the pathogenesis of Anti-Ku autoimmunity, but no research exist on this topic.

OBJECTIVE

We aimed to define the most probable microbial triggers of anti-Ku autoimmunity via molecular mimicry. Materials and methods. We performed a computer-assisted search for amino acid sequence homologies between the two subunits of human Ku and proteins of known human pathogens.

RESULTS

Some fungal, but no bacterial or viral, proteins have statistically significant amino acid sequence homology with the p70 or p80 subunit of Ku. Twenty-six fungal proteins contain long segments highly homologous to p70 (14 proteins) or p80 (12 proteins) and belong to human pathogens (Aspergillus clavatus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, Aspergillus terreus, Chaetomium globosum, Cryptococcus neoformans, Coccidioides immitis, Malassezia globosa, Neosartorya fischeri, Penicillium chrysogenum Wisconsin, Penicillium marneffei, and Yarrowia lipolytica). Twelve p70-homologous and eleven p80-homologous segments span at least one T cell epitope-containing part of the respective human Ku subunit (in the other cases, overlap is almost complete).

DISCUSSION AND CONCLUSION

We postulate that, in genetically predisposed persons, infection by the above fungi can be a trigger in the onset of anti-Ku autoimmunity via molecular mimicry between fungal proteins and the Ku autoantigen. Due to the low frequency of anti-Ku autoimmunity, multicentric collaboration is necessary to verify our hypothesis.

Structure and serology of O-antigens as the basis for classification of Proteus strains

This review is devoted to structural and serological characteristics of the O-antigens (O-polysaccharides) of the lipopolysaccharides of various Proteus species, which provide the basis for classifying Proteus strains to Oserogroups. The antigenic relationships of Proteus strains within and beyond the genus as well as their O-antigenrelated bioactivities are also discussed.

Rheumatoid arthritis and smoking: putting the pieces together

Besides atherosclerosis and lung cancer, smoking is considered to play a major role in the pathogenesis of autoimmune diseases. It has long been known that there is a connection between rheumatoid factor-positive rheumatoid arthritis and cigarette smoking. Recently, an important gene-environment interaction has been revealed; that is, carrying specific HLA-DRB1 alleles encoding the shared epitope and smoking establish a significant risk for anti-citrullinated protein antibody-positive rheumatoid arthritis. We summarize how smoking-related alteration of the cytokine balance, the increased risk of infections (the possibility of cross-reactivity) and modifications of autoantigens by citrullination may contribute to the development of rheumatoid arthritis.

Abnormal immunological profile and vaginal microbiota in women prone to urinary tract infections

The host determinants of susceptibility to recurrent urinary tract infections (UTI) are poorly understood. We investigated whether the susceptibility is associated with abnormalities in the immunological defense and further explored the linkage to vaginal microbiota. For this purpose, we compared vaginal, urine, and blood samples collected during a disease-free period from 22 women with recurrent UTI and from 17 controls. In UTI-prone women, interleukin-12 (IL-12) production in peripheral monocytes and myeloid dendritic cells (DCs) was significantly (P < 0.05) enhanced whether measured in relative numbers of IL-12-producing cells or in mean IL-12 production per cell. In contrast, no T-cell polarization was observed. Interestingly, it seemed that the cytokine production of DCs and monocytes did not translate into T-cell activation in the UTI-prone group in a manner similar to that seen with the controls. In vaginal mucosa, UTI-prone women had a lower concentration of tissue repair-associated vascular endothelial growth factor (VEGF) (P = 0.006) and less often had detectable amounts of the chief monocyte and DC chemoattractant, monocyte chemotactic protein 1 (P = 0.005), than the controls. The microbiota of UTI-prone women was characterized by a diminished lactobacillus morphotype composition, with an abnormally high (>3) mean Nugent score of 4.6 compared to 1.7 for the controls (P = 0.003). Normal lactobacillus composition was associated with increased IL-17 and VEGF concentrations in vaginal mucosa. In conclusion, immunological defects and a persistently aberrant microbiota, a lack of lactobacilli in particular, may contribute to susceptibility to recurrent UTI. Further studies of antigen-presenting-cell function and T-cell activation in recurrent UTI are called for.

Environmental factors and genetic background that interact to cause autoimmune thyroid disease

PURPOSE OF REVIEW

To provide an updated list of genetic and environmental causative factors of autoimmune thyroid disease, and report about the recent discoveries concerning their interaction in the pathogenesis of thyroid autoimmunity.

RECENT FINDINGS

Although significant discoveries have been made on genetic and environmental factors underlying the development of autoimmune thyroid disease, few data are available about the mechanisms by which they interact. The most interesting news in this field comes from research on molecular mimicry between microbial antigens and thyroid autoantigens. The molecular mimicry model postulates that, in predisposed subjects, a microbial antigen could trigger autoimmunity because of its structural similarity to an autoantigen of the host, and is a paradigmatic example of the multifactorial interaction of several genes and environmental factors to cause autoimmune diseases, including thyroid diseases.

SUMMARY

Recent findings help us to better understand the functional mechanisms of the immune system, which are still only partially known. Beyond the scientific interest, this knowledge has immediate repercussions on clinical practice because it can suggest possible therapeutic targets for new treatments, as well as better and more specific uses of currently available drugs and resources.

Clinical Applications of the Polymerase Chain Reaction: An Update

The development, in the past decade, of nucleic acid amplification and detection methods is useful in the study of the etiopathogenesis, diagnosis, and management of a variety of clinical (including rheumatologic) disorders. An association between infectious agents and rheumatic disorders has been established through such methods as polymerase chain reaction. This article describes the principles behind polymerase chain reaction-based diagnosis and updates its clinical applications. It is beyond the scope of this article, however, to describe other nucleic acid amplification methods or to include a complete list of all polymerase chain reaction assays that have been developed. Other recent reviews offer additional details.